1. Field of the Invention
This invention relates generally to semiconductor manufacturing, and, more particularly, to a method and apparatus for performing fault detection using data, such as real-time data from a database, such as a database.
2. Description of the Related Art
The technology explosion in the manufacturing industry has resulted in many new and innovative manufacturing processes. Today's manufacturing processes, particularly semiconductor manufacturing processes, call for a large number of important steps. These process steps are usually vital, and therefore, require a number of inputs that are generally fine-tuned to maintain proper manufacturing control.
The manufacture of semiconductor devices requires a number of discrete process steps to create a packaged semiconductor device from raw semiconductor material. The various processes, from the initial growth of the semiconductor material, the slicing of the semiconductor crystal into individual wafers, the fabrication stages (deposition, etching, ion implanting, or the like), to the packaging and final testing of the completed device, are so different from one another and specialized that the processes may be performed in different manufacturing areas or locations that contain different control schemes.
Generally, a set of processing steps is performed on a group of semiconductor wafers, sometimes referred to as a lot. For example, a process layer composed of a variety of materials may be formed above a wafer. Thereafter, a patterned layer of photoresist may be formed above the process layer using known photolithography techniques. Typically, an etch process is then performed on the process layer using the patterned layer of photoresist as a mask. This etching process results in formation of various features or objects in the process layer. Such features may be used for a variety of purposes, e.g., in a gate electrode structure for transistors. The manufacturing tools within a semiconductor manufacturing facility typically communicate with a manufacturing framework or a network of processing modules. Each manufacturing tool is generally connected to an equipment interface. The equipment interface is connected to a machine interface to which a manufacturing network is connected, thereby facilitating communications between the manufacturing tool and the manufacturing framework. The machine interface can generally be part of an advanced process control (APC) system. The APC system initiates a control script, which can be a software program that automatically retrieves the data needed to execute a manufacturing process.
FIG. 1 illustrates a typical semiconductor wafer 105. The wafer 105 typically includes a plurality of individual semiconductor die 155 arranged in a grid 150. Photolithography steps are typically performed by a stepper on approximately one to four die locations at a time, depending on the specific photomask employed. Photolithography steps are generally performed to form patterned layers of photoresist above one or more process layers that are to be patterned. The patterned photoresist layer can be used as a mask during etching processes, wet or dry, performed on the underlying layer or layers of material, e.g., a layer of polysilicon, metal or insulating material, to transfer the desired pattern to the underlying layer. The patterned layer of photoresist is comprised of a plurality of features, e.g., line-type features or opening-type features that are to be replicated in an underlying process layer.
Turning now to FIG. 2, one example of a block diagram representation of a typical manufacturing process flow is illustrated. A manufacturing system prompts a first processing tool to perform a process upon a plurality of semiconductor wafer 105 (block 210). A manufacturing data acquisition tool (e.g., a metrology tool) then analyzes at least some of the processed semiconductor wafers 105 (block 220), and produces offline metrology data. The metrology data acquired is then analyzed in a data analysis tool, e.g., a computer. The analyzed data can then be used to adjust various parameters related to manufacturing control of subsequent processes in order to reduce any effects of existing manufacturing errors (block 230). Once the manufacturing data analysis is performed, manufacturing data for fault detection is made available to the manufacturing system (block 240). Many times, the manufacturing data is stored in a database, for later retrieval. Often, the flow of the manufacturing process occurs at such a rate that manufacturing data for fault detection is not timely available.
In addition to offline metrology data, manufacturing data relating to the state of the processing tool and data relating to the process itself may be acquired. Often, a large amount of real-time data may be acquired during processing of semiconductor wafers 105. However, processing the acquired real-time data in an efficient manner in order to use the data to improve manufacturing of semiconductor wafers 105 may be difficult using state-of-the-art systems. Often, real-time data acquired during semiconductor manufacturing processes may go under-utilized or even unused.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.